Composition comprising polypyrrolidone polymer dissolved in ferric chloride solution and process for preparing same



Unite State coMPOsmoN ooMPrirsnvo POLYPYRRoLmoNa POLYMER DISSOLVED IN nnnnro ontonmn SOLUTION AND PRocEss FOR rnnrnnnvo SAD/E William B. Black, Decatur, Ala., assignor to The Chemstrand Corporation, Decatur, Ala., a corporation of Delaware No Drawing. Filed Mar. 21, 1960, Ser. No. 16,141 19 Claims. (Cl. 260-291) Polypyrrolidone possesses many excellent properties which make it desirable for utilization in the manufacture of end products, such as ribbons, films, fibers, filaments, rods, bristles, lacquers, coatings, shaped articles and the like. Polypyrrolidone can be converted into shaped articles in many ways. For example, it may be cast into films or forced through multi-hole spinnerets to form tibers or filaments. Regardless Of'the end use to which the polypyrrolidone is to be put, it is generally more convenient and efiicient to employ the polymer in a solution. This is well illustrated in the textile industry where polypyrrolidone is employed in the formation of fibers and filaments, which are manufactured by several methods of spinning, such as melt spinning, dry spinning and wet spinning.

In the melt spinning method, the polymer is heated to a high temperature until it becomes molten, and is thereafter forced through filter media, and thence through a spinneret from whence it is extruded in filamentary form. This method has, however, many disadvantages, although it is widely used in the industry at the present time in the production of synthetic fibers and filaments. The high temperatures used in melt spinning require the exercise of extreme care in order to prevent the decomposition of the polymer. Furthermore the high temperatures also atfect the physical and chemical characteristics of the polymer and thereby result in a product of inferior quality. In addition to these disadvantages, it is extremely difficult to add to the molten polymer at such high tempera tures compounds suchas dyes, anti-static agents, light stabilizers, and the like.

In the dry spinning method of fiber formation, the polymer is dissolved in a suitable solvent and subsequently extruded from spinnerets into a heated atmosphere in order to evaporate the solvent. Even this method, however, has its disadvantages, since during the period of time in which the solvent evaporates, considerable damage may be inflicted on the fibers because of the high heat necessary to bring about solvent evaporation. Another disadvantage of the dry spinning method, and of the melt spinning method also, is the added cost necessary to maintain such high temperatures needed to manufacture the desired end product.

The wet spinning method obviates many of the disadvantages of both melt spinning and dry spinning. In order to form filaments by the wet spinning method, the polymer is dissolved in a suitable solvent and extruded from a spinneret into a coagulating bath capable of leaching the solvent from the fibers. Normally, this method may be carried out at temperatures much lower than either the melt spinning or the dry spinning methods. If it is desired to use additives, such as dyes, anti-static agents, fire-retarding agents, light stabilizers and the like, in the polymeric solution, they maybe incorporated therein without the danger of decomposition or seriously affecting the properties of the end product where the wet spinning method of filamentary formation is employed. It is much easier to introduce such additives into a solution than to introduce them into a molten composition. Then again, solutions are much easier to handle during processing, and in many cases may be stored for long periods of time without a change of physical and chemical properties. It is much easier to cast a film from a solution than to cast it from a molten composition. It is readily apparent, therefore, that solutions of polypyrrolidone possess many distinct advantages Over molten compositions in the manufacture of end products.

Accordingly, it is a primary object of the present invention to provide :new and useful compositions of matter comprising polypyrrolidone. It is a further object of the invention to provide solutions of polypyrrolidone which may be converted into shaped articles, such as ribbons, films, filaments, rods, fibers, bristles, and the like. It is still another object of the invention to provide a process for the preparation of clear, viscous, spinnable solutions from polypyrrolidone polymer and a solvent which is noncorrosive and easily handled.

In general, the objects of the invention are accomplished by dissolving polypyrrolidone in a solution of ferric chloride to form a homogeneous mixture. In the practice of this invention, ferric chloride is normally employed only in solution and not in its normal solid crystalline form.

Suitable compounds which may be utilized to form a solution of ferric chloride comprise water, saturated aliphatic alcohols containing from 1 to 2 carbon atoms, and halogenated saturated aliphatic alcohols containing 2 carbon atoms. As examples of such alcohols there may be named methanol, ethanol, ethylene glycol, 2-bromo-ethanol, 2- ehloro-ethanol, 2,2-dichloro-ethanol, 2-fiuoro-ethanol, and 2,2,2-trichloroethanol. It has been found, contrary to expectations, that higher alcohols, such as propanoht-butanol and butenediol, when used to form a solvent solution of ferric chloride, render the solvent solution ineffective as a solvent for polypyrrolidone. The ferric chloride is usually employed in a range of 25 to 40 percent based on the total weight of the solvent solution. The invention is practiced at room temperature or at slightly elevated temperature, depending on-the nature of the polymer and the concentrations of polymer and solvent solution employed.

It will be readily apparent to those skilled in the art that polypyrrolidone can be dissolved in the solvent solution of this invention in widely varying concentrations.

-When the solution is to be used in the manufacture of fibers and'filaments it is preferred to employ from about 15 to 25 percent polymer, based On the total weight of the polymer solution. From about 10 to 30 percent of the poly-mer, based on the total weight of the polymer solution, may be dissolved in the solvent solution of this invention when the polymer solution is to be used for other are preferred asa practical matter in bringing about so'- lution, temperatures as low as 20 C. and up to theboil- Patented May 8, 1562 suitable for the production of fibers and films.

3 a solution may be employed to ing point ofthe polymer bring about dissolution.

Polypyrrolidone soluble in the solvent solution of this invention may be prepared by various processes. Gena erally, however, polymeric pyrrolidone is prepared by polymerizing 2-pyrrolidonein-the-presence of a catalyst or a catalyst and an activator at a temperature in a range of -70 C. to 100 C., with a range of 20 C. to 70 C. preferred. Polymer prepared in the presence of both acatalyst and an activator has greatly improved propsuspension or bulk polymerization procedures. The so lotion and emulsion polymerizations may be either batch,

I semi-continuous or continuous methods; a The polypyrrolidone compositions which-are useful in the practice of the present invention have a wide range ofmolecuiar weight, from about 3500 to 500,000 The preferred molecular weight range for the preparation of fibers is from 8500 to 50,000. Polymers of lower molecular weight may be used for coatings and films and higher molecular weight polymers may be used for mold ing shapes and similar articles. Specific viscosity of polypyrrolidone with a molecular weight of from about 3500 to 500,000 is in a range of from about 0.2 to 9.4 or more. Viscosity determinations are made by allowing asolution containing a 0.5 percent, concentration of the polypyrrolidone in 90 percent formic acid to-flow by'gravity' at 25 C. through a capillary viscosity tube. a

The following examples are intended to illustrate the new compositions of'this invention more'fully but are not intended as limitative, as many widely varying modi fications thereof are possible. In the examples all parts and percents are'by weight unless otherwise indicated. 7

Example I 1 gram of polypyrrolidone, having a specific'viscosity 050.9, was easily dissolved in 2 grams ferric chloride (25 C.) to give a clear solution of moderate viscosity; The solution was suitable for the-production of fibers and films by wet or dry spinning methods.

Example 11 i n 1 gram of polypyrrolidone, having a: specific viscosity of about 0.6, was easily dissolved in 2 grams ferric chloride hexahydrate and 2 grams'absolute ethanol at room temperature (25 C.) to give-a clean-viscous solution Example ill 1 gram of'polypyrrolidone, having a specific viscosity of about 0.6, was easily dissolved in 2 grams ferric chloride hexahydrate and 2 grams ethylene chlorohydrln at 75 C. to give a clear, viscous solution suitable for the production of fibers and films. f f

Polypyrrolidone polymers having'widely varied .mo lecular weightsgive'like results when dissoved in the sol vent solution of this invention.

As many widely apparently difierent embodiments of this invention may be made without departing from the spirit and scope thereoflit is to be understood that the same is' not to be limited to'the specific embodiments thereof exceptas defined in the appended claims.

Organic metallic compounds, preferably those ing from 1 to 2 carbon atoms, and halogenated saturated" aliphatic alcohols containing 2 carbon atoms.

2. The composition defined in claim lwhereinthe solvent solution comprisesferric chloride dissolved iii-water.

- 3. The composition defined in claim 1 wherein the solvent solution comprises ferric chloride dissolved in ethanol.

4. The composition definedin claim 1 wherein the sol vent solution comprises ferric chloride dissolved in ethylene chlorohydrin.

, 5. The composition defined in claim 1 wherein the solvent' solution comprises ferric chloride dissolved in ethylene glycol.

6. A new composition of matter comprisingfrom 10 to 30 percent based on the total weightcf the composition, of polypyrrolidone dissolved in 70 to 90 percent, based on the total weight of the composition, of a sol vent solution comprising 25. to 40 percent, based on the total weight of the solvent solution, of ferric chloride and to 75 percent, based on the total weight of the solvent solution, of a compound taken from the group consisting of water, saturated aliphatic alcohols containing from 1 to 2 carbon atoms, and halogenated saturated aliphatic alcohols containing 2 carbonatoms.

7. The composition defined'in claim 6 wherein the solvent solution comprises ferric chloride dissolved in water.

8. The composition defined'in claim 6 wherein the solvent solution comprises ferric chloride dissolved in ethanol. 7

9. The composition defined in claim 6wherein the solvent solution comprises ferric chloridedissolvedin ethyl- 1 one chlorohydrin;

10. The composition defined in claimo wherein the solvent solution comprises ferric chloride-dissolved in ethylene glycol.

11. A new fiber forming composition of mattercomprising from 15 to 25 percent, based onthe total'wei'ght' of the composition, of polypyrrolidone dissolved in 75 to percent, based on thetotal Weight of'the'composition, of a solvent solution comprisin'g'25 c0 40 percent, based on the total weight of the solvent solution, of ferricchloride and 60 to 75 percent, based on the t'otal weight of the solvent solution, of a compound taken from the group consisting of water, saturated aliphatic alcohols containv ing from 1 to 2 carbon atoms, and halogenated saturated aliphatic alcohols containing learbon atoms. I

12. The composition definedin claim i=1 wherein the solvent solution comprises: ferric chloride "dissolved in water. 7

13. The compositiondefined in claim 11 wherein the solvent solution comprises ferric chloride dissolved in ethanol. I

14. The'composition defined in-claim ll wherein the solvent solutionv comprises ferric chloride dissolved in ethylene chlorohydrin.

15. The composition 'definedin claim 11 wherein the solvent solution comprises ferric. chloride dissolved in ethylene glycol.

16. A process for preparinga new composition of matter comprising mixing polypyrrolidonewand a'solvent solution comprising ferric chloride dissolved in a compound taken from the group consistingof water, saturated ali-' phatic alcohols. containing from 1 to 2 carbon-atoms and halogenated saturated aliphatic alcohols containing 2 carbon atoms, and heating'the mixture to a temperature in a range of 20 C. to the-boiling point of the mixture to form a homogeneous-solution.

17. The process defined in claim 16 wherein the sol- 3,033,310 5 6 vent solution comprises ferric chloride dissolved in water. solution comprises ferric chloride dissolved in ethylene 18. The process defined in claim 16 wherein the solchlorohydrin.

vent solution comprises ferric chloride dissolved in th L References Cited in the file of this patent 19. The process defined in claim 16 wherein the solvent 5 UNITED STATES PATENTS 2,927,906 Schlack Mar. 8, 1960 

1. A NEW COMPOSITION OF MATTER COMPRISING POLYPYRROLIDONE DISSOLVED IN A SOLVENT SOLUTION COMPRISING FERRIC CHLORIDE DISSOLVED IN A COMPOUND TAKEN FROM THE GROUP CONSISTING OF WATER, SATURATED ALIPHATIC ALCOHOLS CONTAINING FROM 1 TO 2 CARBON ATOMS, AND HALOGENATED SATURATED ALIPHATIC ALCOHOLS CONTAINING 2 CARBON ATOMS. 